<?php

/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-webat this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Session
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: DbTable.php 18951 2009-11-12 16:26:19Z alexander $
 */

/**
 * @see Zend_Session
 */
require_once 'Zend/Session.php';

/**
 * @see Zend_Db_Table_Abstract
 */
require_once 'Zend/Db/Table/Abstract.php';

/**
 * @see Zend_Db_Table_Row_Abstract
 */
require_once 'Zend/Db/Table/Row/Abstract.php';

/**
 * @see Zend_Config
 */
require_once 'Zend/Config.php';

/**
 * Zend_Session_SaveHandler_DbTable
 *
 * @category   Zend
 * @package    Zend_Session
 * @subpackage SaveHandler
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Session_SaveHandler_DbTable
extends Zend_Db_Table_Abstract
implements Zend_Session_SaveHandler_Interface
{
	const PRIMARY_ASSIGNMENT                   = 'primaryAssignment';
	const PRIMARY_ASSIGNMENT_SESSION_SAVE_PATH = 'sessionSavePath';
	const PRIMARY_ASSIGNMENT_SESSION_NAME      = 'sessionName';
	const PRIMARY_ASSIGNMENT_SESSION_ID        = 'sessionId';

	const MODIFIED_COLUMN   = 'modifiedColumn';
	const LIFETIME_COLUMN   = 'lifetimeColumn';
	const DATA_COLUMN       = 'dataColumn';

	const LIFETIME          = 'lifetime';
	const OVERRIDE_LIFETIME = 'overrideLifetime';

	const PRIMARY_TYPE_NUM         = 'PRIMARY_TYPE_NUM';
	const PRIMARY_TYPE_PRIMARYNUM  = 'PRIMARY_TYPE_PRIMARYNUM';
	const PRIMARY_TYPE_ASSOC       = 'PRIMARY_TYPE_ASSOC';
	const PRIMARY_TYPE_WHERECLAUSE = 'PRIMARY_TYPE_WHERECLAUSE';

	/**
	 * Session table primary key value assignment
	 *
	 * @var array
	 */
	protected $_primaryAssignment = null;

	/**
	 * Session table last modification time column
	 *
	 * @var string
	 */
	protected $_modifiedColumn = null;

	/**
	 * Session table lifetime column
	 *
	 * @var string
	 */
	protected $_lifetimeColumn = null;

	/**
	 * Session table data column
	 *
	 * @var string
	 */
	protected $_dataColumn = null;

	/**
	 * Session lifetime
	 *
	 * @var int
	 */
	protected $_lifetime = false;

	/**
	 * Whether or not the lifetime of an existing session should be overridden
	 *
	 * @var boolean
	 */
	protected $_overrideLifetime = false;

	/**
	 * Session save path
	 *
	 * @var string
	 */
	protected $_sessionSavePath;

	/**
	 * Session name
	 *
	 * @var string
	 */
	protected $_sessionName;

	/**
	 * Constructor
	 *
	 * $config is an instance of Zend_Config or an array of key/value pairs containing configuration options for
	 * Zend_Session_SaveHandler_DbTable and Zend_Db_Table_Abstract. These are the configuration options for
	 * Zend_Session_SaveHandler_DbTable:
	 *
	 * primaryAssignment => (string|array) Session table primary key value assignment
	 *      (optional; default: 1 => sessionId) You have to assign a value to each primary key of your session table.
	 *      The value of this configuration option is either a string if you have only one primary key or an array if
	 *      you have multiple primary keys. The array consists of numeric keys starting at 1 and string values. There
	 *      are some values which will be replaced by session information:
	 *
	 *      sessionId       => The id of the current session
	 *      sessionName     => The name of the current session
	 *      sessionSavePath => The save path of the current session
	 *
	 *      NOTE: One of your assignments MUST contain 'sessionId' as value!
	 *
	 * modifiedColumn    => (string) Session table last modification time column
	 *
	 * lifetimeColumn    => (string) Session table lifetime column
	 *
	 * dataColumn        => (string) Session table data column
	 *
	 * lifetime          => (integer) Session lifetime (optional; default: ini_get('session.gc_maxlifetime'))
	 *
	 * overrideLifetime  => (boolean) Whether or not the lifetime of an existing session should be overridden
	 *      (optional; default: false)
	 *
	 * @param  Zend_Config|array $config      User-provided configuration
	 * @return void
	 * @throws Zend_Session_SaveHandler_Exception
	 */
	public function __construct($config)
	{
		if ($config instanceof Zend_Config) {
			$config = $config->toArray();
		} else if (!is_array($config)) {
			/**
			 * @see Zend_Session_SaveHandler_Exception
			 */
			require_once 'Zend/Session/SaveHandler/Exception.php';

			throw new Zend_Session_SaveHandler_Exception(
                '$config must be an instance of Zend_Config or array of key/value pairs containing '
                . 'configuration options for Zend_Session_SaveHandler_DbTable and Zend_Db_Table_Abstract.');
		}

		foreach ($config as $key => $value) {
			do {
				switch ($key) {
					case self::PRIMARY_ASSIGNMENT:
						$this->_primaryAssignment = $value;
						break;
					case self::MODIFIED_COLUMN:
						$this->_modifiedColumn = (string) $value;
						break;
					case self::LIFETIME_COLUMN:
						$this->_lifetimeColumn = (string) $value;
						break;
					case self::DATA_COLUMN:
						$this->_dataColumn = (string) $value;
						break;
					case self::LIFETIME:
						$this->setLifetime($value);
						break;
					case self::OVERRIDE_LIFETIME:
						$this->setOverrideLifetime($value);
						break;
					default:
						// unrecognized options passed to parent::__construct()
						break 2;
				}
				unset($config[$key]);
			} while (false);
		}

		parent::__construct($config);
	}

	/**
	 * Destructor
	 *
	 * @return void
	 */
	public function __destruct()
	{
		Zend_Session::writeClose();
	}

	/**
	 * Set session lifetime and optional whether or not the lifetime of an existing session should be overridden
	 *
	 * $lifetime === false resets lifetime to session.gc_maxlifetime
	 *
	 * @param int $lifetime
	 * @param boolean $overrideLifetime (optional)
	 * @return Zend_Session_SaveHandler_DbTable
	 */
	public function setLifetime($lifetime, $overrideLifetime = null)
	{
		if ($lifetime < 0) {
			/**
			 * @see Zend_Session_SaveHandler_Exception
			 */
			require_once 'Zend/Session/SaveHandler/Exception.php';
			throw new Zend_Session_SaveHandler_Exception();
		} else if (empty($lifetime)) {
			$this->_lifetime = (int) ini_get('session.gc_maxlifetime');
		} else {
			$this->_lifetime = (int) $lifetime;
		}

		if ($overrideLifetime != null) {
			$this->setOverrideLifetime($overrideLifetime);
		}

		return $this;
	}

	/**
	 * Retrieve session lifetime
	 *
	 * @return int
	 */
	public function getLifetime()
	{
		return $this->_lifetime;
	}

	/**
	 * Set whether or not the lifetime of an existing session should be overridden
	 *
	 * @param boolean $overrideLifetime
	 * @return Zend_Session_SaveHandler_DbTable
	 */
	public function setOverrideLifetime($overrideLifetime)
	{
		$this->_overrideLifetime = (boolean) $overrideLifetime;

		return $this;
	}

	/**
	 * Retrieve whether or not the lifetime of an existing session should be overridden
	 *
	 * @return boolean
	 */
	public function getOverrideLifetime()
	{
		return $this->_overrideLifetime;
	}

	/**
	 * Open Session
	 *
	 * @param string $save_path
	 * @param string $name
	 * @return boolean
	 */
	public function open($save_path, $name)
	{
		$this->_sessionSavePath = $save_path;
		$this->_sessionName     = $name;

		return true;
	}

	/**
	 * Close session
	 *
	 * @return boolean
	 */
	public function close()
	{
		return true;
	}

	/**
	 * Read session data
	 *
	 * @param string $id
	 * @return string
	 */
	public function read($id)
	{
		$return = '';

		$rows = call_user_func_array(array(&$this, 'find'), $this->_getPrimary($id));

		if (count($rows)) {
			if ($this->_getExpirationTime($row = $rows->current()) > time()) {
				$return = $row->{$this->_dataColumn};
			} else {
				$this->destroy($id);
			}
		}

		return $return;
	}

	/**
	 * Write session data
	 *
	 * @param string $id
	 * @param string $data
	 * @return boolean
	 */
	public function write($id, $data)
	{
		$return = false;

		$data = array($this->_modifiedColumn => time(),
		$this->_dataColumn     => (string) $data);

		$rows = call_user_func_array(array(&$this, 'find'), $this->_getPrimary($id));

		if (count($rows)) {
			$data[$this->_lifetimeColumn] = $this->_getLifetime($rows->current());

			if ($this->update($data, $this->_getPrimary($id, self::PRIMARY_TYPE_WHERECLAUSE))) {
				$return = true;
			}
		} else {
			$data[$this->_lifetimeColumn] = $this->_lifetime;

			if ($this->insert(array_merge($this->_getPrimary($id, self::PRIMARY_TYPE_ASSOC), $data))) {
				$return = true;
			}
		}

		return $return;
	}

	/**
	 * Destroy session
	 *
	 * @param string $id
	 * @return boolean
	 */
	public function destroy($id)
	{
		$return = false;

		if ($this->delete($this->_getPrimary($id, self::PRIMARY_TYPE_WHERECLAUSE))) {
			$return = true;
		}

		return $return;
	}

	/**
	 * Garbage Collection
	 *
	 * @param int $maxlifetime
	 * @return true
	 */
	public function gc($maxlifetime)
	{
		$this->delete($this->getAdapter()->quoteIdentifier($this->_modifiedColumn) . ' + '
		. $this->getAdapter()->quoteIdentifier($this->_lifetimeColumn) . ' < '
		. $this->getAdapter()->quote(time()));

		return true;
	}

	/**
	 * Calls other protected methods for individual setup tasks and requirement checks
	 *
	 * @return void
	 */
	protected function _setup()
	{
		parent::_setup();

		$this->_setupPrimaryAssignment();
		$this->setLifetime($this->_lifetime);

		$this->_checkRequiredColumns();
	}

	/**
	 * Initialize table and schema names
	 *
	 * @return void
	 * @throws Zend_Session_SaveHandler_Exception
	 */
	protected function _setupTableName()
	{
		if (empty($this->_name) && basename(($this->_name = session_save_path())) != $this->_name) {
			/**
			 * @see Zend_Session_SaveHandler_Exception
			 */
			require_once 'Zend/Session/SaveHandler/Exception.php';

			throw new Zend_Session_SaveHandler_Exception('session.save_path is a path and not a table name.');
		}

		if (strpos($this->_name, '.')) {
			list($this->_schema, $this->_name) = explode('.', $this->_name);
		}
	}

	/**
	 * Initialize session table primary key value assignment
	 *
	 * @return void
	 * @throws Zend_Session_SaveHandler_Exception
	 */
	protected function _setupPrimaryAssignment()
	{
		if ($this->_primaryAssignment === null) {
			$this->_primaryAssignment = array(1 => self::PRIMARY_ASSIGNMENT_SESSION_ID);
		} else if (!is_array($this->_primaryAssignment)) {
			$this->_primaryAssignment = array(1 => (string) $this->_primaryAssignment);
		} else if (isset($this->_primaryAssignment[0])) {
			array_unshift($this->_primaryAssignment, null);

			unset($this->_primaryAssignment[0]);
		}

		if (count($this->_primaryAssignment) !== count($this->_primary)) {
			/**
			 * @see Zend_Session_SaveHandler_Exception
			 */
			require_once 'Zend/Session/SaveHandler/Exception.php';

			throw new Zend_Session_SaveHandler_Exception(
                "Value for configuration option '" . self::PRIMARY_ASSIGNMENT . "' must have an assignment "
                . "for each session table primary key.");
		} else if (!in_array(self::PRIMARY_ASSIGNMENT_SESSION_ID, $this->_primaryAssignment)) {
			/**
			 * @see Zend_Session_SaveHandler_Exception
			 */
			require_once 'Zend/Session/SaveHandler/Exception.php';

			throw new Zend_Session_SaveHandler_Exception(
                "Value for configuration option '" . self::PRIMARY_ASSIGNMENT . "' must have an assignment "
                . "for the session id ('" . self::PRIMARY_ASSIGNMENT_SESSION_ID . "').");
		}
	}

	/**
	 * Check for required session table columns
	 *
	 * @return void
	 * @throws Zend_Session_SaveHandler_Exception
	 */
	protected function _checkRequiredColumns()
	{
		if ($this->_modifiedColumn === null) {
			/**
			 * @see Zend_Session_SaveHandler_Exception
			 */
			require_once 'Zend/Session/SaveHandler/Exception.php';

			throw new Zend_Session_SaveHandler_Exception(
                "Configuration must define '" . self::MODIFIED_COLUMN . "' which names the "
                . "session table last modification time column.");
		} else if ($this->_lifetimeColumn === null) {
			/**
			 * @see Zend_Session_SaveHandler_Exception
			 */
			require_once 'Zend/Session/SaveHandler/Exception.php';

			throw new Zend_Session_SaveHandler_Exception(
                "Configuration must define '" . self::LIFETIME_COLUMN . "' which names the "
                . "session table lifetime column.");
		} else if ($this->_dataColumn === null) {
			/**
			 * @see Zend_Session_SaveHandler_Exception
			 */
			require_once 'Zend/Session/SaveHandler/Exception.php';

			throw new Zend_Session_SaveHandler_Exception(
                "Configuration must define '" . self::DATA_COLUMN . "' which names the "
                . "session table data column.");
		}
	}

	/**
	 * Retrieve session table primary key values
	 *
	 * @param string $id
	 * @param string $type (optional; default: self::PRIMARY_TYPE_NUM)
	 * @return array
	 */
	protected function _getPrimary($id, $type = null)
	{
		$this->_setupPrimaryKey();

		if ($type === null) {
			$type = self::PRIMARY_TYPE_NUM;
		}

		$primaryArray = array();

		foreach ($this->_primary as $index => $primary) {
			switch ($this->_primaryAssignment[$index]) {
				case self::PRIMARY_ASSIGNMENT_SESSION_SAVE_PATH:
					$value = $this->_sessionSavePath;
					break;
				case self::PRIMARY_ASSIGNMENT_SESSION_NAME:
					$value = $this->_sessionName;
					break;
				case self::PRIMARY_ASSIGNMENT_SESSION_ID:
					$value = (string) $id;
					break;
				default:
					$value = (string) $this->_primaryAssignment[$index];
					break;
			}

			switch ((string) $type) {
				case self::PRIMARY_TYPE_PRIMARYNUM:
					$primaryArray[$index] = $value;
					break;
				case self::PRIMARY_TYPE_ASSOC:
					$primaryArray[$primary] = $value;
					break;
				case self::PRIMARY_TYPE_WHERECLAUSE:
					$primaryArray[] = $this->getAdapter()->quoteIdentifier($primary) . ' = '
					. $this->getAdapter()->quote($value);
					break;
				case self::PRIMARY_TYPE_NUM:
				default:
					$primaryArray[] = $value;
					break;
			}
		}

		return $primaryArray;
	}

	/**
	 * Retrieve session lifetime considering Zend_Session_SaveHandler_DbTable::OVERRIDE_LIFETIME
	 *
	 * @param Zend_Db_Table_Row_Abstract $row
	 * @return int
	 */
	protected function _getLifetime(Zend_Db_Table_Row_Abstract $row)
	{
		$return = $this->_lifetime;

		if (!$this->_overrideLifetime) {
			$return = (int) $row->{$this->_lifetimeColumn};
		}

		return $return;
	}

	/**
	 * Retrieve session expiration time
	 *
	 * @param Zend_Db_Table_Row_Abstract $row
	 * @return int
	 */
	protected function _getExpirationTime(Zend_Db_Table_Row_Abstract $row)
	{
		return (int) $row->{$this->_modifiedColumn} + $this->_getLifetime($row);
	}
}
